# Exploring the post-mortem interval through blood biochemistry: a preliminary case series study and review of the literature

## TL;DR

This study explores how blood chemistry changes after death to estimate the time since death, focusing on enzymes like CPK and LDH.

## Contribution

The study introduces a preliminary case series showing that CPK and LDH levels increase predictably post-mortem, following an exponential trend.

## Key findings

- CPK and LDH blood levels show a significant and consistent increase after death.
- The increase in enzyme levels follows an exponential function with a time-dependent growth rate.
- Low interindividual variation suggests potential reliability for estimating post-mortem interval.

## Abstract

Post-mortem biochemistry can be included among the methods reported in the literature to investigate the time since death. To address this issue, we collected blood samples from hospitalized patients who died in the presence of health personnel. Samples were collected 20 min after death and every 6 h until 24 h post-mortem, with the last Ante Mortem (A.M.) sample also included in the analyses. Each sample was immediately centrifuged and analyzed. Our preliminary results indicate a significant and consistent increase in phosphokinase (CPK) and lactodehydrogenase (LDH) blood levels, with low interindividual variation among subjects. Interestingly, the measured time trend follows an exponential function, characterized by a time-dependent growth rate. While a larger sample size is needed to confirm our preliminary findings, our results suggest that CPK and LDH blood levels could be valuable parameters for determining the post-mortem interval. Furthermore, our data were systematically compared to those reported in the literature, which was carefully reviewed.

The online version contains supplementary material available at 10.1007/s00414-025-03576-1.